1. Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly to apparatus and methods for improved user equipment (UE) capability signaling.
2. Background
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
In the current 3GPP HSPA standards, at radio resource control (RRC) connection setup, a user equipment (UE) sends UE radio access capability information as part of the RRC setup complete message to the radio network controller (RNC). UE capability information includes UE radio capabilities, UE non-access stratum (NAS) capabilities, and Classmark information. UE radio capabilities include UE GSM/enhanced data rates for GSM evolution (EDGE) radio access network (GERAN) capability, UE UTRAN capability (includes dynamic security parameters START_PS, START_CS, FRESH_PS) and UE evolved universal terrestrial radio access network (E-UTRAN) capability. UE NAS capabilities include UE network capability and mobile switching (MS) network capability. Classmark information is used for circuit switched (CS) domain which may not be applicable to machine type communication (MTC) devices. In the existing standard, UE reports radio capability at each RRC connection establishment. Also, in addition to the full set of UE radio capability information sent in the RRC connection setup complete message (which may be used for the proper set up of data radio bearers and measurement control configuration), the UE also reports a small set of capabilities in the RRC connection request message (e.g., as initial information to the RNC to properly setup signaling radio bearers). The size of the UE capability information sent in the RRC setup complete message may vary between 124 bytes and 625 bytes in the current 3GPP standard. For an MTC device with a comparable size of data to send (or receive) in each RRC connection, the signaling overhead due to the UE capability information is very large. As such, in order to reduce the radio signaling overhead and also increase the battery life of the UEs, it is desirable to reduce the number of signaling messages sent over the radio interface for machine-to-machine (M2M) and MTC UEs and applications. Furthermore, number of MTC devices in each cell can be very large, and therefore by optimizing the UE signaling messages over the air, both the UE and the UTRAN may benefit.
As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications. Thus, in this case, there is a desire to reduce the signaling messages in UE capability signaling.